Kinda late here, but I thought I'd add some thoughts.
First, the "T" stands for "transgender" or simply "trans." It does not specifically mean "transsexual," which is a more specific label not accepted by all trans people.
"I'm not gay but my husband is" makes perfect sense if the person wearing it is a bisexual man. Likewise, a non-binary, but masculine-presenting person might wear such a shirt, as a gay man could plausible be married to such a person.
"Queer" is a pretty open label. In some cases, folks will use to to denote "genderqueer" or "gender fluid" or some identity among the myriad of non-binary genders. However, it is also used in a manner similar to bisexual, to denote that "gender doesn't matter."
In practice, it is often used as a cultural marker, to suggest the person has some non-normative sexual or gender identity, but who does not "mesh" with the conventional gay/lesbian social scene.
Myself, I find the whole "alphabet soup of suffering" to be rather tedious. However, I also find it not worth arguing about.
I usually describe myself as "queer."
The WPATH standards of care do not suggest hormone treatment for anyone under age sixteen. Before that, they recommend hormone blockers, which are a very different thing. In short, blockers delay the onset of puberty. They are reversible. If the child later decides to proceed with puberty according to their natal sex, they can stop the blockers and puberty will start. If they, at age sixteen, still believe they are transgender, then hormone replacement therapy can begin.
This is not without cost, in that the child will go through puberty later than their peers. However, it is the most humane option.
Puberty is irreversible. Its effects can be hellish to a transgender person. Hormone blockers give the child a few extra years to make a very difficult decision.
No one gets any kind of genital surgery before age 18. Honestly, the waiting lists tend to be over a year, the costs quite high, the required "gatekeeping" quite onerous, and few adults can arrange genital surgery in any rapid way. I've never met someone who had genital surgery before their mid 20s. In fact, most who get it do so quite a bit later than that. Furthermore, many trans people never do, for a variety of reasons.
The idea that "trans kids" are getting irreversible medical interventions is nonsense.